Quantification of parametric uncertainties induced by irregular soil loading in orchard tower sprayer nonlinear dynamics

Cunha, Americo; Félix, Jorge Luis Palacios; Balthazar, José Manoel

doi:10.1016/j.jsv.2017.07.023

Cited by 5 publications

(4 citation statements)

References 26 publications

(40 reference statements)

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“…for 0.15 < x e < 0.30 m 0.01 for x e > 0.30 (5) while stochastic profile [17] is suitable for analyzing the steady-state behaviour and can be modelled using Equation 6 [18]:…”

Section: Road Profilementioning

confidence: 99%

Performance Analysis of an Asymmetric Damper Suspension on Rough Roads and Steps

Ribeiro

2023

Preprint

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This paper analyzes the advantages of employing an asymmetric suspension compared to a symmetric suspension. The road profiles considered are rough roads and steps, and the optimization parameters include comfort and safety. The optimal suspension is achieved using the Cross-Entropy method, and the obtained results for each profile are contradictory. Asymmetric dampers confer specific advantages over symmetric counterparts, notably in their ability to mitigate transient vibrations experienced during steps. However, their advantage becomes less pronounced during steady-state vibrations induced by rough road conditions. The results obtained show that if a suspension is optimized for steps, the resulting configuration is asymmetric. On the other hand, for rough roads, the resulting configuration is symmetric. This disparity indicates that the optimization of an asymmetric suspension must consider a combination of both scenarios.

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“…for 0.15 < x e < 0.30 m 0.01 for x e > 0.30 (5) while stochastic profile [17] is suitable for analyzing the steady-state behaviour and can be modelled using Equation 6 [18]:…”

Section: Road Profilementioning

confidence: 99%

Performance Analysis of an Asymmetric Damper Suspension on Rough Roads and Steps

Ribeiro

2023

Preprint

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“…It is known that mechanical systems and structures are subjected to uncertainties that have to be considered in the processes of models identification and damage detection procedures, as it was exemplified in Section 1. So, taking the uncertainties into account is essential to make robust predictions [54]. The data uncertainties considered are related with environmental or operating conditions, temperature and humidity changes, sensor bonding conditions, that can generate variations in the fundamental frequencies and damping ratios of the structures and systems, making difficult the application of damage detection procedures [55].…”

Section: Stochastic Version Of the Nonlinear Systemmentioning

confidence: 99%

Damage detection in uncertain nonlinear systems based on stochastic Volterra series

Villani

Silva

Cunha

2019

Mechanical Systems and Signal Processing

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The damage detection problem in mechanical systems, using vibration measurements, is commonly called Structural Health Monitoring (SHM). Many tools are able to detect damages by changes in the vibration pattern, mainly, when damages induce nonlinear behavior. However, a more difficult problem is to detect structural variation associated with damage, when the mechanical system has nonlinear behavior even in the reference condition. In these cases, more sophisticated methods are required to detect if the changes in the response are based on some structural variation or changes in the vibration regime, because both can generate nonlinearities. Among the many ways to solve this problem, the use of the Volterra series has several favorable points, because they are a generalization of the linear convolution, allowing the separation of linear and nonlinear contributions by input filtering through the Volterra kernels. On the other hand, the presence of uncertainties in mechanical systems, due to noise, geometric imperfections, manufacturing irregularities, environmental conditions, and others, can also change the responses, becoming more difficult the damage detection procedure. An approach based on a stochastic version of Volterra series is proposed to be used in the detection of a breathing crack in a beam vibrating in a nonlinear regime of motion, even in reference condition (without crack). The system uncertainties are simulated by the variation imposed in the linear stiffness and damping coefficient. The results show, that the nonlinear analysis done, considering the high order Volterra kernels, allows the approach to detect the crack with a small propagation and probability confidence, even in the presence of uncertainties.

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“…Monte Carlo simulations of the stochastic dynamics reveal a wide range of possible responses for the mechanical system, and show the possibility of large lateral vibrations being developed during the sprayer operation. Preliminary results of this work were presented in [2], and deeper analysis of this problem, including a more complex stochastic loading, can be found in [3].…”

Section: Final Remarksmentioning

confidence: 99%

“…This process uses an equipment, called sprayer tower, which is illustrated in Figure 1. This equipment is composed by a vehicle suspension and a support tower, equipped with several fans, and in a typical operating condition it vibrates nonlinearly [8,3]. Understanding the dynamics of this equipment is essential to its design and also to discover operating conditions that may be harmful to the spraying process.…”

Section: Introductionmentioning

confidence: 99%

Exploring the Nonlinear Stochastic Dynamics of an Orchard Sprayer Tower Moving Through an Irregular Terrain

Cunha

Félix

Balthazar

2017

Springer Proceedings in Physics

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In agricultural industry, the process of orchards spraying is of extreme importance to avoid losses and reduction of quality in the products. In orchards spraying process an equipment called sprayer tower is used. It consists of a reservoir and fans mounted over an articulated tower, which is supported by a vehicle suspension. Due to soil irregularities this equipment is subject to random loads, which may hamper the proper dispersion of the spraying fluid. This work presents the construction of a consistent stochastic model of uncertainties to describe the non-linear dynamics of an orchard sprayer tower. In this model, the mechanical system is described by as a multi-body with three degrees of freedom, and random loadings as a harmonic random process. Uncertainties are taken into account through a parametric probabilistic approach, where maximum entropy principle is used to specify random parameters distributions. The propagation of uncertainties through the model is computed via Monte Carlo method.

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Quantification of parametric uncertainties induced by irregular soil loading in orchard tower sprayer nonlinear dynamics

Cited by 5 publications

References 26 publications

Performance Analysis of an Asymmetric Damper Suspension on Rough Roads and Steps

Performance Analysis of an Asymmetric Damper Suspension on Rough Roads and Steps

Damage detection in uncertain nonlinear systems based on stochastic Volterra series

Exploring the Nonlinear Stochastic Dynamics of an Orchard Sprayer Tower Moving Through an Irregular Terrain

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